Epigallocatechin-3-gallate potently inhibits the in vitro activity of hydroxy-3-methyl-glutaryl-CoA reductase

Effects of green tea on lipid profile in overweight and obese women

The effect of green tea administration on serum lipids' concentrations remains unclear as various investigations, which have explored this topic, have produced conflicting results. Gender might be one of the factors influencing the impact of green tea on the lipid profile. Hence, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess the effect of green tea intake on the lipid profile in overweight and obese women. We searched five databases (Web of Science, SCOPUS, Embase, PubMed/Medline, and Google Scholar) using a combination of MeSH and non-MeSH terms. Results were expressed as weighted mean differences (WMDs) and 95% confidence intervals (CIs) and synthesized with a random-effects model. In total, 15 eligible RCTs with 16 arms (1818 participants) were included in the meta-analysis. The combined effect size revealed a significant reduction in total cholesterol (TC) (WMD: -4.45 mg/dl, 95% CI: -6.63, -2.27, P<0.001) and low-density lipoprotein cholesterol (LDL-C) (WMD: -4.49 mg/dl, 95% CI: -7.50 to -1.47, P=0.003) concentrations following green tea supplementation in overweight and/or obese women. In addition, a more pronounced reduction of triglyceride (TG) levels occurred when the baseline TG value was ≥150 mg/dL (WMD: -24.45 mg/dL, 95% CI: -40.63 to -8.26, P=0.003). Moreover, a significant decrease in TG concentrations occurred in RCTs conducted on overweight subjects (BMI: 25-29.99 kg/m2) (WMD: -5.88 mg/dl, 95% CI: -10.76 to -0.99, P=0.01). In the subgroup analyses based on the study population, a notable increase in high-density lipoprotein cholesterol (HDL-C) values was observed in obese individuals (>30 kg/m2) (WMD: 2.63 mg/dl, 95% CI: 0.10 to 5.16, P=0.041). Consumption of green tea causes a reduction in LDL-C and TC concentrations in overweight and obese women. The decline in TG levels was notable particularly in overweight patients with hypertriglyceridemia at baseline. In addition, a significant increase in HDL-C was detected in obese subjects following intake of green tea.

Understanding the (epi)genetic dysregulation in Parkinson's disease through an integrative brain competitive endogenous RNA network

Parkinson's disease (PD) is a rapidly growing neurodegenerative disorder characterized by dopaminergic neuron loss in the substantia nigra pars compacta (SN) and aggregation of α-synuclein. Its aetiology involves a multifaceted interplay among genetic, environmental, and epigenetic factors. We integrated brain gene expression data from PD patients to construct a comprehensive regulatory network encompassing messenger RNAs (mRNAs), microRNAs (miRNAs), circular RNAs (circRNAs) and, for the first time, RNA binding proteins (RBPs). Expression data from the SN of PD patients and controls were systematically selected from public databases to identify combined differentially expressed genes (DEGs). Brain co-expression analysis revealed modules comprising significant DEGs that function cooperatively. The relationships among co-expressed DEGs, miRNAs, circRNAs, and RBPs revealed an intricate competitive endogenous RNA (ceRNA) network responsible for post-transcriptional dysregulation in PD. Many genes in the ceRNA network, including the TOMM20 and HMGCR genes, overlap with the most relevant genes in our previous Alzheimer's disease-associated ceRNA network, suggesting common underlying mechanisms between both conditions. Moreover, in the ceRNA subnetwork, the RBP Aly/REF export factor (ALYREF), which acts as an RNA 5-methylcytosine(m5C)-binding protein, stood out. Our data sheds new light on the potential role of brain ceRNA networks in PD pathogenesis.

The associations between dietary flavonoid intake and hyperlipidemia: data from the national health and nutrition examination survey 2007-2010 and 2017-2018

Background

Hyperlipidemia is a worldwide health problem and a significant risk factor for cardiovascular diseases; therefore, it imposes a heavy burden on society and healthcare. It has been reported that flavonoids can increase energy expenditure and fat oxidation, be anti-inflammatory, and reduce lipid factor levels, which may reduce the risk of hyperlipidemia. However, the relationship between the prevalence of hyperlipidemia and dietary flavonoid intake in the population remains unclear.

Methods

This study included 8,940 adults from the 2007-2010 and 2017-2018 National Health and Nutrition Examination Surveys (NHANES). The relationship between dietary flavonoid intake and the prevalence of hyperlipidemia was analyzed using weighted logistic regression and weighted restricted cubic spline.

Results

We found an inverse relationship between subtotal catechins intake and hyperlipidemia prevalence in the third quartile [0.74 (0.56, 0.98), p = 0.04] compared with the first quartile. The prevalence of hyperlipidemia and total flavan-3-ol intake in the third quartile were inversely correlated [0.76 (0.59, 0.98), p = 0.03]. Total anthocyanin intake was inversely related to the prevalence of hyperlipidemia in the third quartile [0.77 (0.62, 0.95), p = 0.02] and the fourth quartile [0.77 (0.60, 0.98), p = 0.04]. The prevalence of hyperlipidemia was negatively correlated with total flavonols intake in the fourth quartile [0.75 (0.60, 0.94), p = 0.02]. Using restricted cubic splines analysis, we found that subtotal catechins intake and total flavan-3-ol intake had a nonlinear relationship with the prevalence of hyperlipidemia.

Conclusion

Our study may provide preliminary research evidence for personalizing improved dietary habits to reduce the prevalence of hyperlipidemia.

The effect of green tea (Camellia sinensis) on lipid profiles and renal function in people with type 2 diabetes and nephropathy: a randomized controlled clinical trial

Introduction

Diabetic nephropathy is one of the most important microvascular complications of diabetes. Despite the modern treatments, herbs or medicinal plants have gained wide attention. One of these herbs is green tea (Camellia sinensis), which may have an impact on renal function, lipid profiles, and HbA1c. However, the evidence for this is unclear and limited. The present study aimed to evaluate the effect of different doses of green tea on these parameters in type 2 diabetes patients (T2DM) with nephropathy.

Methods

Sixty-six individuals with T2DM nephropathy (aged 30-70 years) were randomly assigned to receive three cups of green tea/day (n = 22), two cups of green tea/day (n = 22), and the control group (n = 22) for 12 weeks. Lipid profiles, glycated hemoglobin A1c (HbA1c), and renal markers were measured before and after intervention. Data were analyzed using SPSS software version 23. One-way analysis of variance (ANOVA), least significant difference (LSD) post hoc, and analysis of covariance were used to compare quantitative variables.

Results

In total, 64 participants completed the study. Consuming three cups of infusion green tea per day (7.5 gr) led to a significant reduction in serum levels of total cholesterol (p = 0.009) and HbA1c (p = 0.006) and increased in high-density lipoprotein cholesterol (HDL-C) (p = 0.02) compared with the control group who did not drink green tea. However, no significant differences were observed for other variables.

Conclusion

In general, it was found that drinking three cups of green tea infusion (7.5 gr) per day produced beneficial effects on some lipid profiles and HbA1c without any adverse effects on renal function in patients with T2DM nephropathy. More studies are needed to fully elucidate these findings.

Clinical trial registration

Iranian Registry of Clinical Trials (www.irct.ir) under registry number: IRCT2014020114538N2.

Multitarget-Directed Gallium(III) Tris(acyl-pyrazolonate) Complexes Induce Ferroptosis in Cancer Cells via Dysregulation of Cell Redox Homeostasis and Inhibition of the Mevalonate Pathway

A series of Ga(Q_n)₃ coordination compounds have been synthesized, where HQ_n is 1-phenyl-3-methyl-4-RC(═O)-pyrazolo-5-one. The complexes have been characterized through analytical data, NMR and IR spectroscopy, ESI mass spectrometry, elemental analysis, X-ray crystallography, and density functional theory (DFT) studies. Cytotoxic activity against a panel of human cancer cell lines was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, with interesting results in terms of both cell line selectivity and toxicity values compared with cisplatin. The mechanism of action was explored by spectrophotometric, fluorometric, chromatographic, immunometric, and cytofluorimetric assays, SPR biosensor binding studies, and cell-based experiments. Cell treatment with gallium(III) complexes promoted several cell death triggering signals (accumulation of p27, PCNA, PARP fragments, activation of the caspase cascade, and inhibition of the mevalonate pathway) and induced changes in cell redox homeostasis (decreased levels of GSH/GPX4 and NADP(H), increased reactive oxygen species (ROS) and 4-hydroxynonenal (HNE), mitochondrial damage, and increased activity of CPR and CcO), identifying ferroptosis as the mechanism responsible for cancer cell death.

Effects of green tea catechins and exercise training on body composition parameters

The impact of phytochemicals, as green tea catechins, on body composition measures has become a relevant topic as ongoing epidemiological evidence suggests their potential role in weight loss. Although catechins have been shown to modulate fat and energy metabolism, clinical effects of green tea consumption still remain controversial. Given the role played by physical exercise in weight management, it is important to determine whether the association of catechins and exercise is able to improve outcomes over and above the beneficial effects of exercise alone. Considering that scientific findings on this topic are not entirely consistent, aim of the present review was to assess the current scientific literature regarding the interplay between green tea catechins and exercise in overweight and obese populations. In particular, it was evaluated whether the addition of green tea supplementation to exercise training was able to further improve the exercise-induced changes in body composition parameters.

Proteomics research of SARS-CoV-2 and COVID-19 disease

Currently, coronavirus disease 2019 (COVID-19) is still spreading in a global scale, exerting a massive health and socioeconomic crisis. Deep insights into the molecular functions of the viral proteins and the pathogenesis of this infectious disease are urgently needed. In this review, we comprehensively describe the proteome of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and summarize their protein interaction map with host cells. In the protein interaction network between the virus and the host, a total of 787 host prey proteins that appeared in at least two studies or were verified by co-immunoprecipitation experiments. Together with 29 viral proteins, a network of 1762 proximal interactions were observed. We also review the proteomics results of COVID-19 patients and proved that SARS-CoV-2 hijacked the host's translation system, post-translation modification system, and energy supply system via viral proteins, resulting in various immune disorders, multiple cardiomyopathies, and cholesterol metabolism diseases.

Spondias purpurea L. Bark Extract Protects against Oxidative Stress and Reduces Hypercholesterolemia in Mice Fed High-Fat Diet

Oxidative stress plays a key role in the initiation and progression of metabolic diseases, including obesity. Preventing the accumulation of reactive oxygen species and oxidative damage to macromolecules is a beneficial strategy for reducing comorbidities associated with obesity. Fruits from the Spondias genus are known for their antioxidant activity, but they are not available year-round due to their seasonality. In this context, we investigated the antioxidant activity and identified the chemical constituents of the aqueous extract of the stem bark of Spondias purpurea L. (EBSp). Additionally, we evaluated the effect of EBSp consumption on metabolic parameters in mice with obesity induced by a high-fat diet. Chemical analyses revealed 19 annotated compounds from EBSp, including flavan-3-ols, proanthocyanidins, methoxylated coumarin, and gallic and ellagic acids, besides other phenolic compounds. In vitro, EBSp showed antioxidant activity through the scavenging of the free radicals and the protection of macromolecules against oxidative damage. Cellular assays revealed that EBSp reduced the levels of malondialdehyde produced by erythrocytes exposed to the oxidizing agent AAPH. Flow cytometry studies showed that EBSp reduced reactive oxygen species levels in human peripheral blood mononuclear cells treated with hydrogen peroxide. Obese mice treated with EBSp (400 mg.kg-1) for 60 days showed reduced levels of malondialdehyde in the heart, liver, kidneys, and nervous system. The total cholesterol levels in mice treated with EBSp reached levels similar to those after treatment with the drug simvastatin. Together, the results show that the combination of the different phenolic compounds in S. purpurea L. bark promotes antioxidant effects in vitro and in vivo, resulting in cytoprotection in the context of oxidative stress associated with obesity and a reduction in hypercholesterolemia. From a clinical perspective, the reduction in oxidative stress in obese individuals contributes to the reduction in the emergence of comorbidities associated with this metabolic syndrome.

Potential dual inhibitors of PCSK-9 and HMG-R from natural sources in cardiovascular risk management

Atherosclerotic cardiovascular disease (ASCVD) stands amongst the leading causes of mortality worldwide and has attracted the attention of world's leading pharmaceutical companies in order to tackle such mortalities. The low-density lipoprotein-cholesterol (LDL-C) is considered the most prominent biomarker for the assessment of ASCVD risk. Distinct inhibitors of 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-R), the chief hepatic cholesterogenic enzyme, are being used since last seven decades to manage hypercholesterolemia. On the other hand, discovery and the association of proprotein convertase subtilisin/kexin type-9 (PCSK-9) with increased ASCVD risk have established PCSK-9 as a novel therapeutic target in cardiovascular medicine. PCSK-9 is well reckoned to facilitate the LDL-receptor (LDL-R) degradation and compromised LDL-C clearance leading to the arterial atherosclerotic plaque formation. The currently available HMG-R inhibitors (statins) and PCSK-9 inhibitors (siRNA, anti-sense oligonucleotides, and monoclonal antibodies) have shown great promises in achieving LDL-C lowering goals, however, their life long prescriptions have raised significant concerns. These deficits associated with the synthetic HMG-R and PCSK-9 inhibitors called for the discovery of alternative therapeutic candidates with potential dual HMG-R and PCSK-9 inhibitory activities from natural origins. Therefore, this report firstly describes the mechanistic insights into the cholesterol homeostasis through HMG-R, PCSK-9, and LDL-R functionality and then compiles the pharmacological effects of natural secondary metabolites with special emphasis on their dual HMG-R and PCSK-9 inhibitory action. In conclusion, various natural products exhibit atheroprotective effects via targeting HMG-R and PCSK-9 activities and lipoprotein metabolism, however, further clinical assessments are still warranted prior their approval for ASCVD risk management in hypercholesterolemic patients.

Potential therapeutic effects of green tea on obese lipid profile - a systematic review

Background: Green tea, obtained from the plant Camellis sinensis, is one of the oldest drinks in the world and contains numerous bioactive compounds. Studies have demonstrated the efficacy of green tea in preventing obesity and cardiovascular diseases that may be related to the reduction of lipid levels. Aim: This study aimed to evidence, through a systematic review, the therapeutic potential of green tea on the lipid profile in preclinical studies in obese animals and clinical studies in obese individuals. Methods: This systematic review follows the recommendations of the preferred report items for systematic reviews and meta-analyses. The electronic databases, PubMed (Medline), Science Direct, Scopus, and Web of Science were consulted. Articles from January 2009 to December 2019 were selected. Results: This search resulted in twenty-nine articles were included cirtically reviewed. In experimental studies, green tea administration has been shown to reduce total cholesterol, triglycerides and low-density lipoprotein cholesterol in animals exposed to obesity-inducing diet. In humans' studies green tea was not shown to be effective for obese lipid control. Because supplementation with green tea extract reduced total cholesterol, triglycerides, low-density lipoprotein for three months at a specific dose. Conclusion: Therefore, green tea appears to act as a protective agent for dyslipidemia in obesity-induced animals. In human studies, green tea has not been shown to be effective in controlling obese lipids.

Flavonoid-statin interactions causing myopathy and the possible significance of OATP transport, CYP450 metabolism and mevalonate synthesis

3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase inhibitors, statins, are a primary treatment for hyperlipidemic cardiovascular diseases which are a leading global cause of death. Statin therapy is life saving and discontinuation due to adverse events such as myotoxicity may lead to unfavourable outcomes. There is no known mechanism for statin-induced myotoxicity although it is theorized that it is due to inhibition of downstream products of the HMG-CoA pathway. It is known that drug-drug interactions with conventional medicines exacerbate the risk of statin-induced myotoxicity, though little attention has been paid to herb-drug interactions with complementary medicines. Flavonoids are a class of phytochemicals which can be purchased as high dose supplements. There is evidence that flavonoids can raise statin plasma levels, increasing the risk of statin-induced myopathy. This could be due to pharmacokinetic interactions involving hepatic cytochrome 450 (CYP450) metabolism and organic anion transporter (OATP) absorption. There is also the potential for flavonoids to directly and indirectly inhibit HMG-CoA reductase which could contraindicate statin-therapy. This review aims to discuss what is currently known about the potential for high dose flavonoids to interact with the hepatic CYP450 metabolism, OATP uptake of statins or their ability to interact with HMG-CoA reductase. Flavonoids of particular interest will be covered and the difficulties of examining herbal products will be discussed throughout.

Green Tea from the Far East to the Drug Store: Focus on the Beneficial Cardiovascular Effects

Cardiovascular diseases (CVD) are the leading cause of death worldwide. Evidence from observational and randomized controlled studies showing the potential benefits of green tea on lowering CVD risk has been emerging rapidly during the past few decades. These benefits include reduced risk for major cardiovascular events, lowering of blood pressure, decreased LDL cholesterol levels and weight loss. At the same time, the understanding of the physiological mechanisms behind these alterations is advancing. Consumption of green tea originated from China thousands of years ago, but since then, it expanded all over the world. Recent advances in understanding the role of tea polyphenols, mainly catechins, as mediators of tea's health benefits, have caused the emergence of various types of green tea extracts (GTE) on the market. While taking green tea is generally considered safe, there are concerns about the safety of using tea extracts. The present article reviews the current evidence of green tea consumption leading to reduced CVD risk, its potential biological mechanisms and the safety of using GTE.

Gene Expression Profile and Co-Expression Network of Pearl Gentian Grouper under Cold Stress by Integrating Illumina and PacBio Sequences

Simple Summary

In this study, we investigated the liver transcriptomic responses of pearl gentian grouper towards cold stress. Some cold-related key genes and biological pathways were screened, of which energy-related metabolic pathways and genes had higher expression levels under cold stress. This suggested that energy homeostasis plays a crucial role in the physiological adjustments of pearl gentian grouper when exposed to the cold stress environment. Our results will expedite the understanding of different fishes adaptive mechanisms to profound environmental temperature changes and provide insights into the molecular breeding of cold-tolerant pearl gentian grouper varieties.

Abstract

Pearl gentian grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂) is a fish of high commercial value in the aquaculture industry in Asia. However, this hybrid fish is not cold-tolerant, and its molecular regulation mechanism underlying cold stress remains largely elusive. This study thus investigated the liver transcriptomic responses of pearl gentian grouper by comparing the gene expression of cold stress groups (20, 15, 12, and 12 °C for 6 h) with that of control group (25 °C) using PacBio SMRT-Seq and Illumina RNA-Seq technologies. In SMRT-Seq analysis, a total of 11,033 full-length transcripts were generated and used as reference sequences for further RNA-Seq analysis. In RNA-Seq analysis, 3271 differentially expressed genes (DEGs), two low-temperature specific modules (tan and blue modules), and two significantly expressed gene sets (profiles 0 and 19) were screened by differential expression analysis, weighted gene co-expression networks analysis (WGCNA), and short time-series expression miner (STEM), respectively. The intersection of the above analyses further revealed some key genes, such as PCK, ALDOB, FBP, G6pC, CPT1A, PPARα, SOCS3, PPP1CC, CYP2J, HMGCR, CDKN1B, and GADD45Bc. These genes were significantly enriched in carbohydrate metabolism, lipid metabolism, signal transduction, and endocrine system pathways. All these pathways were linked to biological functions relevant to cold adaptation, such as energy metabolism, stress-induced cell membrane changes, and transduction of stress signals. Taken together, our study explores an overall and complex regulation network of the functional genes in the liver of pearl gentian grouper, which could benefit the species in preventing damage caused by cold stress.

Ultrasound Assisted Extraction of Phenolic Compounds from a Jujube By-Product with Valuable Bioactivities

Jujube plant is a potential source of polyphenols with biological propreties. The purpose of this study was to investigate the application of ultrasound technique for extracting phenolic compounds (TPC) from seeds of Zizyphus lotus under optimization conditions based on response surface methodology. A maximum TPC, total flavonoids content (TFC), and total condensed tannins content (TTC) of 2383.10 ± 0.87 mg GAE/100g, 486.50 ± 0.38 mg QE/100g and 15,787.10 ± 0.10 mg CE/100g, respectively obtained under ethanol concentration 50.16%, sonication temperature 29.01 °C, sonication time 15.94 min and solvent-to-solid ratio 34.10:1 mL/g. The optimized extract was then evaluated for its antioxidant, antiacethylcholinesterase, antihypercholesterolemia, and antiproliferative activities. The results showed that ultrasound method is a green and safe method that can be used to effectively extract TPC from jujube seeds. The biological activity of Zizyphus extract exhibited a very good antioxidant against DPPH (EC50 = 0.39 µg/mL) and FRAP (1670.42 ± 6.5 mg/100 g). Additionally, it possesses acetylcholinesterase (AChE) inhibitory effect (IC50 = 0.93 ± 0.01 mg/mL) and HMGR inhibition (45.41%) using 100 µg/mL. The extract significantly inhibits cell proliferation on the MCF-7 and HepG2 tumor cell lines with an IC50 values of <0.05 and 3 ± 0.55 mg/mL, respectively. Therefore, the ultrasound method can be considered a method for obtaining a significant anticancer activity with respect to the lines and therefore makes it possible to recover a maximum of phenolic compounds in less time with an AChE and HMGR inhibitory activity. Thus, it can be suggested that Zls extract is a promising fruit for the development of supplementary dietary due to its potential behaviour as nutraceutical.

Structure/activity virtual screening and in vitro testing of small molecule inhibitors of 8-hydroxy-5-deazaflavin:NADPH oxidoreductase from gut methanogenic bacteria

Virtual screening techniques and in vitro binding/inhibitory assays were used to search within a set of more than 8,000 naturally occurring small ligands for candidate inhibitors of 8-hydroxy-5-deazaflavin:NADPH oxidoreductase (FNO) from Methanobrevibacter smithii, the enzyme that catalyses the bidirectional electron transfer between NADP⁺ and F420H₂ during the intestinal production of CH₄ from CO₂. In silico screening using molecular docking classified the ligand-enzyme complexes in the range between - 4.9 and - 10.5 kcal/mol. Molecular flexibility, the number of H-bond acceptors and donors, the extent of hydrophobic interactions, and the exposure to the solvent were the major discriminants in determining the affinity of the ligands for FNO. In vitro studies on a group of these ligands selected from the most populated/representative clusters provided quantitative kinetic, equilibrium, and structural information on ligands' behaviour, in optimal agreement with the predictive computational results.

Effect of the herbal medicines in obesity and metabolic syndrome: A systematic review and meta-analysis of clinical trials

Obesity is a medical situation in which excess body fat has gathered because of imbalance between energy intake and energy expenditure. In spite of the fact that the variety of studies are available for obesity treatment and management, its "globesity" still remains a big challenge all over the world. The current systematic review and meta-analysis aimed to evaluate the efficacy, safety, and mechanisms of effective herbal medicines in the management and treatment of obesity and metabolic syndrome in human. We systematically searched all relevant clinical trials via Web of Science, Scopus, PubMed, and the Cochrane database to assess the effects of raw or refined products derived from plants or parts of plants on obesity and metabolic syndrome in overweight and obesity adult subjects. All studies conducted by the end of May 2019 were considered in the systematic review. Data were extracted independently by two experts. The quality assessment was assessed using Consolidated Standards of Reporting Trials checklist. The main outcomes were anthropometric indices and metabolic syndrome components. Pooled effect of herbal medicines on obesity and metabolic syndrome were presented as standardized mean difference (SMD) and 95% confidence interval (CI). A total of 279 relevant clinical trials were included. Herbals containing green tea, Phaseolus vulgaris, Garcinia cambogia, Nigella sativa, puerh tea, Irvingia gabonensis, and Caralluma fimbriata and their active ingredients were found to be effective in the management of obesity and metabolic syndrome. In addition, C. fimbriata, flaxseed, spinach, and fenugreek were able to reduce appetite. Meta-analysis showed that intake of green tea resulted in a significant improvement in weight ([SMD]: -0.75 [-1.18, -0.319]), body mass index ([SMD]: -1.2 [-1.82, -0.57]), waist circumference ([SMD]: -1.71 [-2.66, -0.77]), hip circumference ([SMD]: -0.42 [-1.02, -0.19]), and total cholesterol, ([SMD]: -0.43 [-0.77, -0.09]). In addition, the intake of P. vulgaris and N. sativa resulted in a significant improvement in weight ([SMD]: -0.88, 95 % CI: [-1.13, -0.63]) and triglyceride ([SMD]: -1.67, 95 % CI: [-2.54, -0.79]), respectively. High quality trials are still needed to firmly establish the clinical efficacy of the plants in obesity and metabolic syndrome.

Exploring the Molecular Mechanisms Underlying the in vitro Anticancer Effects of Multitarget-Directed Hydrazone Ruthenium(II)-Arene Complexes

The molecular targets and the modes of action behind the cytotoxicity of two structurally established N,O- or N,N-hydrazone ruthenium(II)-arene complexes were explored in human breast adenocarcinoma cells (MCF-7) and paralleled in non-cancerous and cisplatin-resistant counterparts (MCF-10A and MCF-7CR respectively). Both complexes, [Ru(hmb)(L1)Cl] (1, L1=4-((2-(2,4-dinitrophenyl)hydrazono)(phenyl)methyl)-3-methyl-1-phenyl-1H-pyrazol-5-olate) and [Ru(cym)(L2)Cl] (2, L2=1-((3-methyl-5-oxo-1-phenyl-1H-pyrazol-4(5H)-ylidene)(phenyl)methyl)-2-(pyridin-2-yl)hydrazin-1-ide), reversibly interact with moderate-to-high affinity with a number of molecular targets in cell-free assays, namely serum albumin, DNA, the 20S proteasome and hydroxymethylglutaryl-CoA reductase. Most interestingly, only 2 readily crosses the cell membrane and preserves its binding/modulatory ability toward the targets of interest upon rapid cellular internalization. The resulting action at multiple levels of the cancer cascade is likely the cause for the selective sensitization of tumour cells to p27-mediated apoptotic death, and for the ability of 2 to overcome the drug resistance problem.

Tea Consumption and Health Outcomes: Umbrella Review of Meta-Analyses of Observational Studies in Humans

SCOPE

The aim of this article is to conduct an umbrella review to study the strength and validity of associations between tea consumption and diverse health outcomes.

METHODS AND RESULTS

Meta-analyses of observational studies examining associations between tea consumption and health outcomes in all human populations and settings are screened. The umbrella review identifies 96 meta-analyses with 40 unique health outcomes. Tea consumption shows greater benefits than harm to health in this review. Dose-response analyses of tea consumption indicates reduced risks of total mortality, cardiac death, coronary artery disease, stroke, and type 2 diabetes mellitus with increment of two to three cups per day. Beneficial associations are also found for several cancers, skeletal, cognitive, and maternal outcomes. Harmful associations are found for esophageal and gastric cancer when the temperature of intake is more than 55-60 °C.

CONCLUSION

Tea consumption, except for very hot tea, seems generally safe at usual levels of intake, with summary estimates indicating the largest reduction for diverse health outcomes at two to three cups per day. Generally, tea consumption seems more beneficial than harmful in this umbrella review. Randomized controlled trials are further needed to understand whether the observed associations are causal.

Effect of green tea consumption on the metabolic syndrome indices in women: a clinical trial study

Purpose

Metabolic syndrome (MetS) is a complex disorder that exacerbates the risk of cardiovascular disease and diabetes mellitus; some studies have indicated the beneficial effects of green tea on human health. The purpose of this study is to investigate the effects of green tea consumption on the MetS indicators in women.

Design/methodology/approach

A randomized clinical trial was carried out on 70 eligible women with confirmed diagnosis of MetS who visited Shabani Diabetes Clinic (Isfahan, Iran). Participants were randomly divided into two groups. Participants in the Green Tea Group were asked to consume three 200 cc of green tea in the morning, at noon and at night for eight weeks, while people in the control group were asked to take identical amount of lukewarm water at the same schedule. Anthropometric indicators, blood pressure, blood sugar, lipid profile, diet and physical activity were assessed at the beginning and the end of the study.

Findings

An independentt-test showed that weight (p =0.001), body mass index (p =0.001), waist circumference (p< 0.001) and waist–hip ratio (p =0.02), systolic blood pressure (p =0.04), fasting blood glucose (p =0.01) and low density lipoprotein (p =0.03) changed significantly more in the Green Tea Group than in the control group; but no such inter-group difference was observed in diastolic blood pressure, triglyceride, total cholesterol and high density lipoprotein (HDL) values (p> 0.05).

Originality/value

Regular consumption of green tea for eight weeks significantly improved anthropometric indices, blood pressure, blood sugar and lipid profile in women with MetS. Therefore, this beverage can serve as part of an effective dietary strategy to control MetS.

Novel osmium(ii)–cymene complexes containing curcumin and bisdemethoxycurcumin ligands

First examples of p-cymene-osmium(ii) curcuminoid complexes with antitumor activity.

MDR reversal and pro-apoptotic effects of statins and statins combined with flavonoids in colon cancer cells

The resistance of cancer cells to a variety of structurally non-related cytotoxic drugs is known as multidrug resistance phenomenon (MDR). In cellular membranes an activity of MDR transporters such as P-glycoprotein (ABCB1) is affected by their lipid environment. Many various compounds have been examined for their ability to restore drug-sensitivity of resistant cancer cells. Statins, inhibitors of the key enzyme of mevalonate pathway HMG-CoA (3-hydroxy-3-methyl-glutaryl-coenzyme A) reductase are drugs commonly prescribed in order to reduce serum level of cholesterol and to diminish the risk of cardiovascular disease. Statins as drugs that influence lipid composition of cell membrane and in that way they also exert influence on lipid bilayer properties appear to be good candidates as MDR modulators. In this work it was shown that statins - mevastatin and simvastatin exert antiproliferative, pro-apoptotic and reversing drug resistance effect in human colon adenocarcinoma cell line LoVo and its drug-resistant subline LoVo/Dx. A hypothesis was also checked whether flavones, which as it is well known are able to influence the biosynthesis of cholesterol, may change the anticancer activity of statins. Our investigations have revealed that combined use of statins and studied flavonoids results in enhanced cell growth inhibition and apoptosis and lower cancer cell proliferation as compared to the application only statins alone. Moreover, in drug resistant LoVo/Dx cells a stronger decrease of resistance to doxorubicine was observed in the presence of statins in combination with flavones as compared to the effect observed for statins only.

Effects of Metformin Combined with Lactoferrin on Lipid Accumulation and Metabolism in Mice Fed with High-Fat Diet

Metformin (Met) and lactoferrin (Lf) both exhibit beneficial effects on body weight management and lipid accumulation. However, the synergistical action of Met and Lf remains unclear. In this study, 64 mice were divided into five groups, namely, the control group, high-fat diet (HFD group), HFD with Met (Met group), Lf (Lf group), and a combination of Met and Lf (Met + Lf group). Met (200 mg/kg body weight) and Lf (2 g/100 mL) were administrated in drinking water. The experiment lasted for 12 weeks. Body weight, serum, and hepatic lipids were determined. Histology of the liver and perirenal fat was observed. Protein expression related to hepatic lipid metabolism was also measured. HFD significantly increased body weight, visceral fat weight, and lipid profiles, which lead to obesity and dyslipidemia in mice. Compared with the HFD group, the treatments significantly decreased body weight and Lee’s index (body mass index of mice) with the lowest values in the Met + Lf group. The treatments also decreased the weight of visceral fat, and improved circulating lipid profile and the ability for regulating glucose intake. The adipocyte size and serum TC level were significantly lower in the Met + Lf group as compared with those in the Met or Lf group. The treatments alleviated hepatic lipid accumulation, especially in the Met + Lf group. For protein expression, the p-AMPK/AMPK ratio, a key kinase-regulating cellular energy homeostasis, was significantly higher in the Met + Lf group than the ratio in the HFD group. Similarly, the treatments significantly downregulated the protein expression of lipogenic enzymes (FAS, ACC, and SREBP-1) and upregulated the protein expression of lipolytic enzyme (ATGL). The protein expression of HMGCoAR, which is an important rate limiting enzyme in cholesterol biosynthesis, was only significantly lower in the Met + Lf group than in the HFD group. In conclusion, Met and Lf, either alone or in combination, prevented HFD-induced obesity and improved lipid metabolism.

Impact of the green tea ingredient epigallocatechin gallate and a short pentapeptide (Ile-Ile-Ala-Glu-Lys) on the structural organization of mixed micelles and the related uptake of cholesterol

BACKGROUND

High levels of blood cholesterol are conventionally linked to an increased risk of developing cardiovascular disease (Grundy, 1986). Here we examine the molecular mode of action of natural products with known cholesterol-lowering activity, such as for example the green tea ingredient epigallocatechin gallate and a short pentapeptide, Ile-Ile-Ala-Glu-Lys.

METHODS

Molecular Dynamics simulations are used to gain insight into the formation process of mixed micelles and, correspondingly, how active agents epigallocatechin gallate and Ile-Ile-Ala-Glu-Lys could possibly interfere with it.

RESULTS

Self-assembly of physiological micelles occurs on the order of 35-50 ns; most of the structural properties of mixed micelles are unaffected by epigallocatechin gallate or Ile-Ile-Ala-Glu-Lys which integrate into the micellar surface; the diffusive motion of constituting lipids palmitoyl-oleoyl-phosphatidylcholine and cholesterol is significantly down-regulated by both epigallocatechin gallate and Ile-Ile-Ala-Glu-Lys; CONCLUSIONS: The molecular mode of action of natural compounds epigallocatechin gallate and Ile-Ile-Ala-Glu-Lys is a significant down-regulation of the diffusive motion of micellar lipids.

GENERAL SIGNIFICANCE

Natural compounds like the green tea ingredient epigallocatechin gallate and a short pentapeptide, Ile-Ile-Ala-Glu-Lys, lead to a significant down-regulation of the diffusive motion of micellar lipids thereby modulating cholesterol absorption into physiological micelles.

In Vitro and In Silico Studies of the Molecular Interactions of Epigallocatechin-3-O-gallate (EGCG) with Proteins That Explain the Health Benefits of Green Tea

Green tea has been shown to have beneficial effects on many diseases such as cancer, obesity, inflammatory diseases, and neurodegenerative disorders. The major green tea component, epigallocatechin-3-O-gallate (EGCG), has been demonstrated to contribute to these effects through its anti-oxidative and pro-oxidative properties. Furthermore, several lines of evidence have indicated that the binding affinity of EGCG to specific proteins may explain its mechanism of action. This review article aims to reveal how EGCG-protein interactions can explain the mechanism by which green tea/EGCG can exhibit health beneficial effects. We conducted a literature search, using mainly the PubMed database. The results showed that several methods such as dot assays, affinity gel chromatography, surface plasmon resonance, computational docking analyses, and X-ray crystallography have been used for this purpose. These studies have provided evidence to show how EGCG can fit or occupy the position in or near functional sites and induce a conformational change, including a quaternary conformational change in some cases. Active site blocking, steric hindrance by binding of EGCG near an active site or induced conformational change appeared to cause inhibition of enzymatic activity and other biological activities of proteins, which are related to EGCG’s biological oligomer and formation of their toxic aggregates, leading to the prevention of neurodegenerative diseases and amyloidosis. In conclusion, these studies have provided useful information on the action of green tea/catechins and would lead to future studies that will provide further evidence for rational EGCG therapy and use EGCG as a lead compound for drug design.

Interfering with the high-affinity interaction between wheat amylase trypsin inhibitor CM3 and toll-like receptor 4: in silico and biosensor-based studies

Wheat amylase/trypsin bi-functional inhibitors (ATIs) are protein stimulators of innate immune response, with a recently established role in promoting both gastrointestinal and extra-gastrointestinal inflammatory syndromes. These proteins have been reported to trigger downstream intestinal inflammation upon activation of TLR4, a member of the Toll-like family of proteins that activates signalling pathways and induces the expression of immune and pro-inflammatory genes. In this study, we demonstrated the ability of ATI to directly interact with TLR4 with nanomolar affinity, and we kinetically and structurally characterized the interaction between these macromolecules by means of a concerted approach based on surface plasmon resonance binding analyses and computational studies. On the strength of these results, we designed an oligopeptide capable of preventing the formation of the complex between ATI and the receptor.

Antioxidants from black and green tea: from dietary modulation of oxidative stress to pharmacological mechanisms

The consumption of tea (Camellia sinensis) has been correlated with a low incidence of chronic pathologies, such as cardiovascular disease and cancer, in which oxidative stress plays a critical role. Tea catechins and theaflavins are, respectively, the bioactive phytochemicals responsible for the antioxidant activity of green tea (GT) and black tea (BT). In addition to their redox properties, tea catechins and theaflavins could have also pharmacological activities, such as the ability to lower glucose, lipid and uric acid (UA) levels. These activities are mediated by pharmacological mechanisms such as enzymatic inhibition and interaction with transporters. Epigallocatechin gallate is the most active compound at inhibiting the enzymes involved in cholesterol and UA metabolism (hydroxy-3-methyl-glutaryl-CoA reductase and xanthine oxidase respectively) and affecting glucose transporters. The structural features of catechins that significantly contribute to their pharmacological effect are the presence/absence of the galloyl moiety and the number and positions of the hydroxyl groups on the rings. Although the inhibitory effects on α-glucosidase, maltase, amylase and lipase, multidrug resistance 1, organic anion transporters and proton-coupled folate transport occur at higher concentrations than those apparent in the circulation, these effects could be relevant in the gut. In conclusion, despite the urgent need for further research in humans, the regular consumption of moderate quantities of GT and BT can effectively modulate their antioxidant capacity, mainly in people subjected to oxidative stress, and could improve the metabolism of glucose, lipid and UA.

LINKED ARTICLES

This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.

Anti-obesogenic and antidiabetic effects of plants and mushrooms

Obesity is reaching global epidemic proportions as a result of factors such as high-calorie diets and lack of physical exercise. Obesity is now considered to be a medical condition, which not only contributes to the risk of developing type 2 diabetes mellitus, cardiovascular disease and cancer, but also negatively affects longevity and quality of life. To combat this epidemic, anti-obesogenic approaches are required that are safe, widely available and inexpensive. Several plants and mushrooms that are consumed in traditional Chinese medicine or as nutraceuticals contain antioxidants, fibre and other phytochemicals, and have anti-obesogenic and antidiabetic effects through the modulation of diverse cellular and physiological pathways. These effects include appetite reduction, modulation of lipid absorption and metabolism, enhancement of insulin sensitivity, thermogenesis and changes in the gut microbiota. In this Review, we describe the molecular mechanisms that underlie the anti-obesogenic and antidiabetic effects of these plants and mushrooms, and propose that combining these food items with existing anti-obesogenic approaches might help to reduce obesity and its complications.

Effects of green tea catechin extract on serum lipids in postmenopausal women: a randomized, placebo-controlled clinical trial

BACKGROUND

Green tea has been suggested to improve cardiovascular disease risk factors, including circulating lipid variables. However, current evidence is predominantly based on small, short-term randomized controlled trials conducted in diverse populations.

OBJECTIVE

The aim of this study was to examine the efficacy and impact of green tea extract (GTE) supplementation high in epigallocatechin gallate (EGCG) on blood lipids in healthy postmenopausal women.

DESIGN

This was an ancillary study of a double-blind, randomized, placebo-controlled, parallel-arm trial investigating the effects of a GTE supplement containing 1315 mg catechins (843 mg EGCG) on biomarkers of breast cancer risk. Participants were randomly assigned to receive GTE (n = 538) or placebo (n = 537) and were stratified by catechol-O-methyltransferase (COMT) genotype activity (high COMT compared with low or intermediate COMT genotype activity). They consumed either 4 GTE or identical placebo capsules daily for 12 mo. A total of 936 women completed this substudy. Circulating lipid panels including total cholesterol (TC), HDL cholesterol, and triglycerides were measured at baseline and at months 6 and 12.

RESULTS

Compared with placebo, 1-y supplementation with GTE capsules resulted in a significant reduction in circulating TC (-2.1% compared with 0.7%; P = 0.0004), LDL cholesterol (-4.1% compared with 0.9%; P < 0.0001) and non-HDL cholesterol (-3.1% compared with 0.4%; P = 0.0032). There was no change in HDL-cholesterol concentration, but triglyceride concentrations increased by 3.6% in the GTE group, whereas they decreased by 2.5% in the placebo group (P = 0.046). A significant reduction in TC was observed only among women with high (i.e., ≥200 mg/dL) baseline TC concentrations (P-interaction = 0.01) who consumed GTE capsules. The effect of GTE on the increase in triglycerides was mainly observed among obese women and statin users (P-interaction = 0.06).

CONCLUSION

Supplementation with GTE significantly reduced circulating TC and LDL-cholesterol concentrations, especially in those with elevated baseline TC concentrations. This trial was registered at clinicaltrials.gov as NCT00917735.

Interaction between wheat alpha-amylase/trypsin bi-functional inhibitor and mammalian digestive enzymes: Kinetic, equilibrium and structural characterization of binding

Alpha-amylase/trypsin bi-functional inhibitors (ATIs) are non-gluten protein components of wheat and other cereals that can hypersensitise the human gastrointestinal tract, eventually causing enteropathies in predisposed individuals. These inhibitory proteins can act both directly by targeting specific pro-inflammatory receptors, and indirectly by impairing the activity of digestive enzymes, the latter event causing the accumulation of undigested peptides with potential immunogenic properties. Herein, according to a concerted approach based on in vitro and in silico methods we characterized kinetics, equilibrium parameters and modes of binding of the complexes formed between wheat ATI and two representative mammalian digestive enzymes, namely trypsin and alpha-amylase. Interestingly, we demonstrated ATI to target both enzymes with independent binding sites and with moderately high affinity.

A Double-Blind, Randomized, Placebo-Controlled Study to Evaluate the Efficacy and Safety of STA-2 (Green Tea Polyphenols) in Patients with Chronic Stable Angina

BACKGROUND

Green tea intake has been shown to improve endurance capacity in animal studies, but whether it has a similar effect on humans remains unclear. A randomized, double-blinded, parallel-controlled study was conducted to evaluate the short-term effect of STA-2, a pharmaceutical preparation of green tea polyphenols, in patients with effort-induced angina and documented positive exercise tolerance test.

METHODS

A total of 79 patients recruited from three medical centers were randomly assigned to receive 2 STA-2 250 mg capsules, each containing 100 mg green tea polyphenols, three times daily, or placebo for six weeks after two consecutive symptom-limited treadmill exercise tests to ascertain the reproducibility of exercise tolerance.

RESULTS

There was no difference in total exercise tolerance time from baseline to Week 6 between two groups (p = 0.639). There were also no observed improvements in subgroup analyses stratified by age, gender, and BMI categories. However, a significant reduction in low-density lipoprotein levels was shown in patients in the STA-2 group (-8.99 ± 19.18 mg/dL) versus the placebo group (0.57 ± 19.77 mg/dL), p = 0.037, with greater benefits in patients not taking antihyperlipidemic drugs (STA-2: -9.10 ± 19.96 mg/dL vs. placebo: 4.42 ± 15.08 mg/dL, p = 0.037).

CONCLUSIONS

STA-2 treatment for 6 weeks did not increase exercise time as measured on a treadmill. However, this study also indicated that STA-2 treatment could have potential beneficial effects on LDL-cholesterol concentrations.

Natural Inhibitors of HMG-CoA Reductase-An Insilico Approach Through Molecular Docking and Simulation Studies

Plant products have always been considered for many important metabolic disorders due to its abundant medicinal properties. Alarming adverse effects of overuse of statins has been reported for patients with dyslipidemia. This study was aimed to identify compounds with potent anti-dyslipidemic property from selected plants and analyze them for their efficiency in binding with HMG-CoA reductase, a key enzyme in lipid metabolism. The docking studies indicate rutin as the best compound that can inhibit HMG-CoA reductase as it had strong binding affinity to the enzyme. The molecular dynamics simulation studies confirmed the stability of the HMG-CoA reductase-rutin complex. RMSD, RMSF, Rg, H-bond results indicated that the HMG-CoA reductase-rutin complex is highly stable. Presently, statins are not preferred for individuals with pre-existing liver disease. Our study identified rutin as a promising lead compound which could be further developed into an anti-dyslipidemic molecule. Our results will be a good starting point for future experimental and clinical studies and if the results from such studies match international standards plant derived rutin might emerge as a good alternative to statins. J. Cell. Biochem. 118: 52-57, 2017. © 2016 Wiley Periodicals, Inc.

Lipid-modifying effects of nutraceuticals: An evidence-based approach

The present review provides an up-to-date summary of the findings on the lipid-lowering effects of the most important nutraceuticals and functional foods. Based on current knowledge, nutraceuticals might exert significant lipid-lowering, and their use has several advantages: A number of important questions remain to be addressed, including whether longer durations of therapy would result in a better response and the exact safety profile of nutraceuticals, especially at doses higher than those consumed in an average diet. Additionally, data regarding the effects of nutraceutical supplementation on the incidence of cardiovascular outcomes are lacking, and it is not clear whether additional lipid lowering by nutraceuticals can modify the residual cardiovascular risk that remains after statin therapy.

A ruthenium derivative of quercetin with enhanced cholesterol-lowering activity

A ruthenium(ii)p-cymene derivative of quercetin was synthesized and functionally tested for cholesterol-lowering abilityviadirect 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGR) inhibition.

Mangiferin blocks proliferation and induces apoptosis of breast cancer cells via suppression of the mevalonate pathway and by proteasome inhibition

Mangiferin is a natural xanthone glycoside with therapeutic potential.

The differential effects of green tea on dose-dependent doxorubicin toxicity

Background

Doxorubicin (DOX) is an anticancer drug displaying cardiac and hepatic adverse effects mostly dependent on oxidative stress. Green tea (GT) has been reported to play a protective role in diseases resulting from oxidative stress.

Objective

The objective of this study was to evaluate if GT protects against DOX-induced oxidative stress, heart and liver morphological changes, and metabolic disorders.

Methods

Male Wistar rats received intraperitoneal injection of DOX (1.0 or 2.0 mg/kg b.w.) for 7 weeks or concomitantly GT extract soluble in drinking water.

Results

There were multidirectional effects of GT on blood metabolic parameters changed by DOX. Among all tested biochemical parameters, statistically significant protection of GT against DOX-induced changes was revealed in case of blood fatty acid–binding protein, brain natriuretic peptide, and superoxide dismutase.

Conclusion

DOX caused oxidative stress in both organs. It was inhibited by GT in the heart but remained unchanged in the liver. DOX-induced general toxicity and histopathological changes in the heart and in the liver were mitigated by GT at a higher dose of DOX and augmented in rats treated with a lower dose of the drug.

Formulation, characteristics and antiatherogenic bioactivities of CD36-targeted epigallocatechin gallate (EGCG)-loaded nanoparticles

Intimal macrophages are determinant cells for atherosclerotic lesion formation by releasing inflammatory factors and taking up oxidized low-density lipoprotein (oxLDL) via scavenger receptors, primarily the CD36 receptor. (-)-Epigallocatechin-3-gallate (EGCG) has a potential to decrease cholesterol accumulation and inflammatory responses in macrophages. We made EGCG-loaded nanoparticles (Enano) using phosphatidylcholine, kolliphor HS15, alpha-tocopherol acetate and EGCG. 1-(Palmitoyl)-2-(5-keto-6-octene-dioyl) phosphatidylcholine (KOdiA-PC), a CD36-targeted ligand found on oxLDL, was incorporated on the surface of Enano to make ligand-Enano (L-Enano). The objectives of this study are to deliver EGCG to macrophages via CD36-targeted L-Enano and to determine its antiatherogenic bioactivities. The optimized nanoparticles obtained in our study were spherical and around 108 nm in diameter, and had about 10% of EGCG loading capacity and 96% of EGCG encapsulation efficiency. Compared to Enano, CD36-targeted L-Enano had significantly higher binding affinity to and uptake by macrophages at the same pattern as oxLDL. CD36-targeted L-Enano dramatically improved EGCG stability, increased macrophage EGCG content, delivered EGCG to macrophage cytosol and avoided lysosomes. L-Enano significantly decreased macrophage mRNA levels and protein secretion of monocyte chemoattractant protein 1, but did not significantly change macrophage cholesterol content. The innovative CD36-targeted nanoparticles may facilitate targeted delivery of diagnostic, preventive and therapeutic compounds to intimal macrophages for the diagnosis, prevention and treatment of atherosclerosis with enhanced efficacy and decreased side effects.

Insight into the mechanism of polyphenols on the activity of HMGR by molecular docking

Statins are hypolipidemic drugs that are effective in the treatment of hypercholesterolemia by attenuating cholesterol synthesis in the liver via competitive inhibition of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase. Recently, dietary changes associated with drug therapy have garnered attention as novel drugs to mitigate or ameliorate hypercholesterolemia. The present study was undertaken to observe different dietary polyphenols that can bind to the active site of HMGR and inhibit it. Results from the 12 dietary polyphenols tested reveal that polyphenols can bind to HMGR and block the binding of nicotinamide adenine dinucleotide phosphate (NADP⁺). We observed that the rigidity of phenolic rings prevents the polyphenols from docking to the enzyme activity site. The presence of an ester linkage between the phenolic rings in (–)-epigallocatechin-3-gallate (EGCG) and the alkyl chain in curcumin allows them to orient in the active site of the HMGR and bind to the catalytic residues. EGCG and curcumin showed binding to the active site residues with a low GRID score, which may be a potential inhibitor of HMGR. Kaempferol showed binding to HMG-CoA, but with low binding affinity. These observations provide a rationale for the consistent hypolipidemic effect of EGCG and curcumin, which has been previously reported in several epidemiological and animal studies. Therefore, this study substantiates the mechanism of polyphenols on the activity of HMGR by molecular docking and provides the impetus for drug design involving further structure–function relationship studies.

Long non-coding RNAs expression profile in HepG2 cells reveals the potential role of long non-coding RNAs in the cholesterol metabolism

BACKGROUND

Green tea has been shown to improve cholesterol metabolism in animal studies, but the molecular mechanisms underlying this function have not been fully understood. Long non-coding RNAs (lncRNAs) have recently emerged as a major class of regulatory molecules involved in a broad range of biological processes and complex diseases. Our aim was to identify important lncRNAs that might play an important role in contributing to the benefits of epigallocatechin-3-gallate (EGCG) on cholesterol metabolism.

METHODS

Microarrays was used to reveal the lncRNA and mRNA profiles in green tea polyphenol(-)-epigallocatechin gallate in cultured human liver (HepG2) hepatocytes treated with EGCG and bioinformatic analyses of the predicted target genes were performed to identify lncRNA-mRNA targeting relationships. RNA interference was used to investigate the role of lncRNAs in cholesterol metabolism.

RESULTS

The expression levels of 15 genes related to cholesterol metabolism and 285 lncRNAs were changed by EGCG treatment. Bioinformatic analysis found five matched lncRNA-mRNA pairs for five differentially expressed lncRNAs and four differentially expressed mRNA. In particular, the lncRNA AT102202 and its potential targets mRNA-3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) were identified. Using a real-time polymerase chain reaction technique, we confirmed that EGCG down-regulated mRNA expression level of the HMGCR and up-regulated expression of AT102202. After AT102202 knockdown in HepG2, we observed that the level of HMGCR expression was significantly increased relative to the scrambled small interfering RNA control (P < 0.05).

CONCLUSIONS

Our results indicated that EGCG improved cholesterol metabolism and meanwhile changed the lncRNAs expression profile in HepG2 cells. LncRNAs may play an important role in the cholesterol metabolism.

Preventive role of green tea catechins from obesity and related disorders especially hypercholesterolemia and hyperglycemia

Background

During the last few years, scientific investigations have proposed diet based regimens to prevent several health ailments including obesity, hypercholesterolemia and diabetes. In this regard, a promising tool is the use of functional foods/nutraceuticals. Present research project was an attempt to explore nutraceutical worth of locally grown green tea variety (Qi-Men) against lifestyle related disorders.

Methods

Functional drinks (T₂ and T₃) were prepared by adding catechins and epigallocatechin gallate (EGCG) @ 550 mg/500 mL and compared with control (T₁). These functional drinks were tested in experimental rats modeling (Sprague Dawley). Based on diets, four studies were conducted i.e. trial-I (normal diet), trial-II (high cholesterol diet), trial-III (high sucrose diet), trial-IV (high cholesterol + high sucrose diet). Rats were monitored daily for their feed and drink intake while body weight was measured on weekly basis. After period of 56 days rats were sacrificed and evaluated their serum lipid (cholesterol, LDL and HDL), glucose and insulin levels.

Results

Results for feed consumption by rats revealed that highest feed intake was recorded in group provided control drink than other groups. However, non significant differences were noted among all groups for drink consumption. Functional drinks resulted in significant reduction in body weight with maximum lowering noted in trial-II and III i.e. 10.73 to 8.49% and 10.12 to 10.49%, respectively. Likewise, cholesterol and LDL were substantially reduced with 14.42% decrease observed in trial-IV and 30.43% in trial-II, respectively. Furthermore, serum glucose and insulin levels were also lowered significantly in the trial-III and IV while in trial-I and II differences were non-significant. In contrast to lipid profile, experimental drink containing EGCG reduced the trait better than catechins based functional drink.

Conclusions

The drinks supplemented with catechins and EGCG are effective against obesity, hypercholesterolemia and hyperglycemia.

Atheroprotective effects of (poly)phenols: a focus on cell cholesterol metabolism

Collated observations from several epidemiological studies have demonstrated that dietary intake of (poly)phenols from nuts, coffee, cocoa, grapes, and berries may protect against the development of atherosclerosis. Whereas this beneficial activity has previously been linked mainly to antioxidant or anti-inflammatory properties, recently emerging data suggest mechanisms by which (poly)phenolic substances can modulate cellular lipid metabolism, thereby mitigating atherosclerotic plaque formation. In this review, both experimental studies and clinical trials investigating the atheroprotective effects of the most relevant dietary (poly)phenols are critically discussed.

Antioxidative effect of epigallocatechin gallate against D-galactosamine-induced injury in primary culture of rat hepatocytes

Literature data support that green tea and its major component epigallocatechin gallate (EGCG) have powerful antioxidant effects. Contrary, hepatotoxicity can be induced by high-dose EGCG. The timing of exposure to green tea in relation to administration of hepatotoxic agent plays an import role too. The aim of our work was a verification of antioxidative effect of EGCG on D-galactosamine-induced injury in primary culture of rat hepatocytes. Hepatocytes were incubated with EGCG at concentrations of 1.25-10 μM and toxic D-galactosamine (GalN) for 24 hrs. Alternatively, hepatocytes were pretreated with EGCG for 24 hrs, and then incubated with EGCG and GalN for further 24 hrs. Cytotoxicity was analysed by lactate dehydrogenase activity, functional capacity by albumin production. Oxidative stress was evaluated from a production of malondialdehyde and glutathione content in the cells. EGCG protected hepatocytes against GalN-induced cytotoxicity but preventive treatment of intact hepatocytes with EGCG was required to diminish the development of hepatocyte injury. Oxidative stress induced in our study seems to overcome the ability of hepatocytes to improve GSH depletion and albumin production. Prolongation of the pretreatment with EGCG could be a promising strategy leading to amelioration of its hepatoprotective effect.

Identification through high-throughput screening of 4'-methoxyflavone and 3',4'-dimethoxyflavone as novel neuroprotective inhibitors of parthanatos

BACKGROUND AND PURPOSE

The current lack of disease-modifying therapeutics to manage neurological and neurodegenerative conditions justifies the development of more efficacious agents. One distinct pathway leading to neuronal death in these conditions and which represents a very promising and attractive therapeutic target is parthanatos, involving overactivation of PARP-1. We therefore sought to identify small molecules that could be neuroprotective by targeting the pathway.

EXPERIMENTAL APPROACH

Using HeLa cells, we developed and optimized an assay for high-throughput screening of about 5120 small molecules. Structure-activity relationship (SAR) study was carried out in HeLa and SH-SY5Y cells for molecules related to the initial active compound. The neuroprotective ability of each active compound was tested in cortical neuronal cultures.

KEY RESULTS

4'-Methoxyflavone (4MF) showed activity by preventing the decrease in cell viability of HeLa and SH-SY5Y cells caused by the DNA-alkylating agent, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), which induces parthanatos. A similar compound from the SAR study, 3',4'-dimethoxyflavone (DMF), also showed significant activity. Both compounds reduced the synthesis and accumulation of poly (ADP-ribose) polymer and protected cortical neurones against cell death induced by NMDA.

CONCLUSIONS AND IMPLICATIONS

Our data reveal additional neuroprotective members of the flavone class of flavonoids and show that methoxylation of the parent flavone structure at position 4' confers parthanatos-inhibiting activity while additional methoxylation at position 3', reported by others to improve metabolic stability, does not destroy the activity. These molecules may therefore serve as leads for the development of novel neurotherapeutics for the management of neurological and neurodegenerative conditions.

Peptides from cowpea present antioxidant activity, inhibit cholesterol synthesis and its solubilisation into micelles

In previous studies, it was reported that the protein isolated from the cowpea interferes favourably in lipid metabolism, and reduces cholesterol synthesis. The present study investigated the role of cowpea peptide fractions in the micellar solubilisation of cholesterol, in the 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) activity, and in the in vitro antioxidant capacity, considering the effects of thermal processing. The protein was isolated from the raw and cooked beans and digested to simulate human digestion. The peptides from the protein isolate of raw bean with molecular mass lower than 3kDa reduced 89% of the HMGCR enzymatic reaction velocity. The cooked cowpeas were more effective in inhibiting the micellar solubility of cholesterol than the raw ones but not the antioxidant activity. This is the first report that cowpea peptides inhibit cholesterol homeostasis in vitro in two distinct routes, and act as an antioxidant.